I was browsing around when I came across this: Full Black Peeping Box Chastity Cuff
I think the device is pretty cool... impractical, but pretty ingenious. I was thinking, you could take it a step forward though and instead of a peeping tom door, why not have a small camera inside? Something like what cell phones have.
It could take pictures and send them using wifi tethering on a smartphone (or even bluetooth to an app that emails periodically). Maybe even write in a GPS API that tracks where your dick is at all times so your keyholder can keep track of you.
I don't have the technical capacity to do something like this... someone want to put it on Kickstarter?? Lol...